T-cell antigen recognition is based on the presentation of antigen fragments (peptides) by molecules of the major histocompatibility complex (MHC) on the surface of antigen presenting cells (APCs). MHC: peptide complexes are recognised by antigen-specific T-cell receptors (TCRs) on the T cell surface, and this recognition can initiate a range of immune responses against the antigen.
Allergic diseases are linked to the ability of some antigens, termed allergens, to induce a hypersensitive immune response. There is a need to identify new molecules which are able to modulate immune responses in situations where the response of the immune system is inappropriate. Identification of such molecules would be of benefit in treatment of allergic diseases.